Grouted anchorages are often used in connection with means for securing faults in a base formation, for example in the case of excavation retaining walls, and for safety in lifting. They consist of one or a plurality of steel braces and an anchoring member formed in the base formation such as the ground. Grouted anchorages of this type are introduced into the soil by various drilling methods and secured there. The anchoring member is secured in the ground by injecting cement mortar once or a plurality of times, which then sets to form the anchorage. The provision of a grouted anchorage in the ground is successful, subject to certain restrictions, even if a water super-pressure builds up behind the wall at the anchoring position.
It is known, when placing grouted anchorages against a small excess hydrostatic pressure to provide seals at the anchoring position which are formed of packings or sleeves and which are located between the propelling tube and the passage in the wall to seal the gap therebetween. It is also known to provide a resilient lip seal which bears resiliently against an anchoring rod having a smaller diameter than the propelling tube once the propelling tube has been removed and which thus prevents the soil under excess hydrostatic pressure behind the wall passage from flowing out. Although the seal remains effective between the wall passage and the propelling tube as the hydrostatic pressure increases, water and particles of soil can penetrate into the propelling tube after ejection therefrom of the drill tip or other drilling tool which remains in the ground. The water and particles of soil can flow out through the tube and thus pass through the retaining wall, an effect which is not acceptable particularly if there are rigid structures located above the anchoring position.